A wireless radio transceiver, also known as User Equipment (UE), mobile station, wireless terminal and/or mobile terminal is enabled to communicate wirelessly in a wireless communication network, sometimes also referred to as a cellular radio system or radio network. The communication may be made, e.g., between two wireless radio transceivers, between a wireless radio transceiver and a wire connected telephone and/or between a receiver and a server via a Radio Access Network (RAN) and possibly one or more core networks.
The wireless communication network covers a geographical area which is divided into cell areas, with each cell area being served by a radio network node, or base station, e.g., a Radio Base Station (RBS), which in some networks may be referred to as transmitter, eNodeB (eNB), NodeB, or B node, depending on the technology and terminology used. The network nodes may be of different classes, e.g., macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size.
In some radio access networks, several radio network nodes may be connected, e.g., by landlines or microwave, to a Radio Network Controller (RNC), e.g., in Universal Mobile Telecommunications System (UMTS). The RNC, also sometimes termed Base Station Controller (BSC), e.g., in Global System for Mobile Communications (GSM), may supervise and coordinate various activities of the plural radio network nodes connected thereto. In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), radio network nodes, which may be referred to as eNodeBs or eNBs, may be connected to a gateway, e.g., a radio access gateway, to one or more core networks.
Systems beyond 3G mobile communication, e.g., 3GPP LTE, offer high data rate by employing Multiple-Input and Multiple-Output (MIMO) with Orthogonal Frequency Division Multiplexing (OFDM) access scheme at the UE receiver. A receiver, before being able to receive data from a serving radio network node, has to perform channel estimation. The channel estimation is based on a reference signal emitted by the radio network node. The quality of such channel estimates is important to support very high data rates, in particular in highly frequency- and time-selective channel (or doubly-selective channel) conditions. However, many techniques employed to perform channel estimation result in errors for high data rates.